How to use it
- Type the Distance in NM and the Ground speed in knots of the leg.
- Type the Burn rate and choose its Unit of the burn rate and the taxi fuel; then choose the Fuel, and type its density if it is another fuel.
- Type the Taxi fuel and the Contingency, then choose the Rules you fly under. For IFR, type the Alternate distance and tick the alternate box when one is required.
- Read Fuel to carry and the Fuel plan table in litres, US gallons and kilograms.
How the trip fuel and the total are found
The trip time is the distance divided by the ground speed. The trip fuel is the burn rate times that time, with the burn rate in litres per hour. The contingency is a percentage of the trip fuel, and the reserve is the burn rate times the time the rule names. The total is the sum of the taxi, the trip, the contingency, the alternate and the reserve.
A quantity in US gallons or kilograms is converted through 3.785411784 litres to the US gallon and through the density to the kilogram: the kilogram is litres times the density in kg per litre.
trip time = distance ÷ ground speed
trip fuel = burn rate × trip time
contingency = trip fuel × contingency %
reserve = burn rate × reserve minutes ÷ 60
total = taxi + trip + contingency + alternate + reserve- Typical densities at 59 °F: AVGAS 6.01 lb per US gallon, which is 0.720 kg per litre; Jet A 6.68 lb per US gallon, which is 0.800 kg per litre (FAA-H-8083-1, Figure 3-4).
- 88 US gallons is 333.1 litres, the handbook's own conversion in its fuel tables (FAA-H-8083-1).
The reserve the rules name
A VFR flight in an airplane must carry enough fuel to fly to the first point of intended landing and then, at normal cruising speed, 30 minutes in the day or 45 minutes at night (14 CFR 91.151(a)). An IFR flight must carry enough to fly to the first airport of intended landing, then to the alternate airport, and then 45 minutes at normal cruising speed (14 CFR 91.167(a)). The IFR alternate is not needed when 91.167(b) allows it, which needs a standard instrument approach and the forecast ceiling and visibility at the destination.
- The reserve is the minimum the rule names. The plan here does not count the wind on the alternate leg or any hold, and it does not replace the fuel policy of an operator.
What this page does not cover
- Wind, which changes the ground speed and the fuel to the destination. Use the forecast wind for the altitude you fly.
- The climb fuel and the descent fuel, which the aircraft's performance data gives.
- The fuel policy of an operator, a holding fuel, and the fuel for a diversion beyond the alternate.
- This page is for training and planning practice, not for real flight.
Worked example: 300 NM at 150 kt, 8 US gallons an hour, day VFR
The trip time is 300 ÷ 150 = 2 h, so the trip fuel is 8 × 2 = 16 US gal, which is 60.6 L. The 5 % contingency is 0.8 US gal and the taxi fuel is 2 US gal.
The day VFR reserve is 30 minutes at 8 US gal an hour, which is 4 US gal, or 15.1 L. The total is 2 + 16 + 0.8 + 4 = 22.8 US gal, which is 86.3 L, or 62.2 kg of AVGAS.
| Item | Value |
|---|---|
| Trip | 16.0 US gal, 60.6 L |
| Reserve (30 min) | 4.0 US gal, 15.1 L |
| Total | 22.8 US gal = 86.3 L = 62.2 kg |
Frequently asked questions
What is the difference between the trip fuel and the fuel to carry?
The trip fuel is only the fuel burned over the distance. The fuel to carry adds the taxi fuel, a contingency and the reserve the rules name, so it is the amount that should be in the tanks when the flight starts.
How much reserve does a VFR flight need?
14 CFR 91.151(a) requires enough fuel to fly to the first point of intended landing and then 30 minutes in the day or 45 minutes at night, at normal cruising speed. Those are minimums.
Why does IFR add the alternate and 45 minutes?
14 CFR 91.167(a) requires enough fuel to reach the destination, then the alternate, then 45 minutes at normal cruising speed. Paragraph (b) removes the alternate when a standard approach and the forecast weather allow it.
Where do the fuel densities come from?
The FAA weight and balance handbook gives AVGAS at 6.01 lb per US gallon and Jet A at 6.68 lb per US gallon at 59 °F. Those are converted to kilograms per litre with 0.45359237 kg per pound and 3.785411784 litres per gallon.
Is the contingency percentage a rule?
No. The regulations name the reserve in minutes, but the contingency is a choice of the pilot or the operator. The page uses a percentage you enter and does not treat it as a rule.
Can I use this plan for a real flight?
No, not on its own. It is for training and planning practice. Use the aircraft's flight manual, your operator's fuel policy and the current weather for a real flight.
Sources
- 14 CFR 91.151 Fuel requirements for flight in VFR conditions (GPO CFR, 2025 edition)
- 14 CFR 91.167 Fuel requirements for flight in IFR conditions (GPO CFR, 2025 edition)
- FAA Aircraft Weight and Balance Handbook FAA-H-8083-1 (fuel weights of Figure 3-4 and the litre conversion)
Figures and text last checked on Tuesday, November 10, 2026.